Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Pararenal and juxtarenal aneurysms are infrarenal aneurysms located within about 5 mm of the renal arteries that have very short necks (i.e., less than 5 mm) or that involve 2-3 visceral arteries (e.g., right and left renal arteries and occasionally the superior mesenteric artery (“SMA”)) and that extend to within about 5 mm of the SMA. Since a pararenal aneurysm typically includes only a portion of the visceral trunk of the aorta, obtaining a proximal seal between a main body stent graft and the vascular tissue is difficult since blood flow must be maintained to the renal arteries, the SMA and the celiac artery. One technique to treat a pararenal aneurysm may involve placing bridging stent grafts in each of the foregoing arteries via a branched or manifold stent graft, for example. While this technique may provide a sufficient proximal seal between the stent graft and the vasculature, the proximal seal may also create a new risk, namely that blood flow to the lumbar arteries may be blocked by the proximal seal. Specifically, the lumbar arteries perfuse the spinal cord with blood, and they tend to be concentrated in the area of the thoracic aorta above the celiac arteries in the “seal zone” for stent grafts placed and anchored in the aorta. As such, cutting off blood flow to the lumbar arteries may cause a patient to become hemodynamically unstable (i.e., blood pressure is too low to sufficiently perfuse tissues with blood) and may put a patient at risk for paraplegia.